A pretty good, open-source, no-pay FAT layer is available at <http://alumnus.caltech.edu/~pje/rdcf2.txt>. The implementation there is limited to FAT16 but can be extended and has a lot of nice features. It requires read_sector() and write_sector() routines to access the logical drive. That means it can interface with floppy drives directly but will require a shim layer to properly access hard drive formated devices like CompactFlash, etc. Regards -Bill Knight R O SoftWare & http://www.theARMPatch.com On Wed, 09 Nov 2005 15:29:35 -0500, Tom Walsh wrote: >seangra wrote: >>Call me crazy, but how is $150 for something that you can get for >>free a good value? There must be dozens of open source FAT drivers >>that could easily be ported, no? Or am I missing something? >> >> >> >You are, there really isn't any "good" FAT layers that are BSD >licensed. Most of what the stuff is very simplistic, only read a file, >and write to a new file. You don't have functions like: overwrite an >existing file, etc. >Take a look at a recent Circuit Cellar, issue 176(?), for the article >"Portable FAT Library for MCU Applications ><http://www.dtweed.com/circuitcellar/caj00176.htm>". That has the >limitation that it will only create a new file, it will not overwrite an >existing file (delete existing and create again). Also, program does >not implement fseek(), although you can make it seek if you alter the code. >IMO, there are two errors in that code as well, one deals with reading >fragmented files, the other is reading from the MMC itself. The example >they give for reading from MMC is flawed. The example works if you read >the WHOLE file at once, subsequent calls to readPartialSector() will >cause the MMC to return garbage data on occasion. >Seems that everyone has $$$ in their eyes when it comes to this stuff: >write-once, charge-many. >I'm in the process of writing my own FAT layer that is integrated into >NewLib (fopen, fclose, fputc, fseek, etc.). The plan is to release the >source under a BSD license. While writing a FAT file driver is not that >hard, it takes time. I was disappointed to find that no one had written >one and released the source! >Regards, >TomW >>--- In lpc2000@yahoogroups.com, "Joel Winarske" <joelw@i...> wrote: >> >> >>>For anyone interested in implementing SD card with FAT12/FAT16 >>> >>> >>support this >> >> >>>is worth a look: >>> >>>http://tinyurl.com/3ozdl >>>-or- >>>http://www.prllc.com/productcart/pc/viewPrd.asp? >>> >>> >>idcategory=10&idproduct=29 >> >> >>>It's a great value. >>> >>>I ported it to IAR, and have it running on an IAR LPC2148 KS board. >>> >>>Joel >>> >>> >> >> >> >> >> >> >> >> >>Yahoo! Groups Links >> >> >> >> >> >> >> >> >-- >Tom Walsh - WN3L - Embedded Systems Consultant >http://openhardware.net, http://cyberiansoftware.com >"Windows? No thanks, I have work to do..." >---------------------------------------------------- > >Yahoo! Groups Links >
Message
[lpc2000] Re: Cheap SD Flash File System
2005-11-10 by Bill Knight